1. Field of the Invention
The present invention relates to a transmission for a hybrid vehicle, in detail, a transmission for a hybrid vehicle having one or more electric vehicle (EV) mode, two power split modes, and multi-fixed gear ratio shift ranges.
2. Description of Related Art
Hybrid vehicles equipped with a hybrid transmission including an engine, a motor generator, and a planetary gear set can travel in an EV mode operated by only a motor usually at the start or low velocity and also in a power split mode allowing more efficiently using the power of the engine and the motor by operating the transmission as an electrically variable transmission (EVT) as the vehicle velocity increases. Further, the hybrid vehicles can use a fixed-gear ratio to improve power performance of the vehicles as in the existing transmissions. Systems based on this conception have contributed to maximize the idle stop function and regenerative brake and to improve fuel efficiency and power performance of vehicles.
Further, hybrid vehicles do not produce exhaust gas from the engine when being driven only by the motor generator and can operate the engine at the best fuel economy point, which is recognized as an environmental-friendly automobile technology having advantages of improving fuel economy and reducing exhaust gas.
The transmissions for the hybrid vehicles are designed to implement a variety of drive modes with a simpler configuration, such that, preferably, the vehicles can be efficiently driven while improving fuel economy and acceleration performance by switching the drive modes in accordance with the traveling conditions of the vehicles, thereby improving the driving performance.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.